The goal of the research is to examine the mechanisms by which the central nervous system mediates various aspects of sociosexual behavior in mammals. There is an emphasis on the hormonal control or modulation of these mechanisms. The medial preoptic-anterior hypothalamic area and other brain structures which have interconnections with this area, such as the amygdalostrial system, are of particular interest. These areas of the brain appear to be critical in the mediation of male sexual behavior and some other sexually dimorphic behavioral patterns. A concept that will be explored is that there are one or more areas of the brain which act as androgen target tissues for the maintenance and activation of male sexual behavior by testosterone. Another aspect of the proposed research is to examine the role of these brain areas in female behavior. The development of neuropsychological concepts that may apply to several mammalian species, including the human species, is of special concern. The comparative approach will be utilized, but the species used in any particular experiment is that which is felt to be the most appropriate for the problem or concept being investigated.